I think we should go back to the Moon and use it as a testing ground for the equipment that we'll need on Mars. After properly working out the issues from that same equipment, then go on to Mars.

The problem with that idea, is that the stuff you need to go to the Moon is nearly all different from the stuff you need to go to Mars.

The environments are very different. Radiation exposure levels and gravity are different. Methods required for landing on the surface are very different. Heating / cooling loads, and how you get rid heat or stay warm are different. Available materials for ISRU are different. and so on.

The landers are definitely different because Mars's high gravity means they need bigger fuel tanks. The extreme heat when passing through Mars's atmosphere will cause big problems necessitating a thermal protection system.

Radiation is only a problem on Mars if the protection designed for the Moon cannot be used. Otherwise the rovers, spacesuits and habitats just end up being heavier.

Many items will be common with the zero-G environment because none of the environments can support human life. However there are weird differences - tables and chairs do not work in zero-G but do on Mars and the Moon.

The landers are definitely different because Mars's high gravity means they need bigger fuel tanks. The extreme heat when passing through Mars's atmosphere will cause big problems necessitating a thermal protection system.

Radiation is only a problem on Mars if the protection designed for the Moon cannot be used. Otherwise the rovers, spacesuits and habitats just end up being heavier.

Many items will be common with the zero-G environment because none of the environments can support human life. However there are weird differences - tables and chairs do not work in zero-G but do on Mars and the Moon.

Good points regarding landers. Overall, the only shared elements for Lunar and Martian landers would be life support and radiation shielding. That does mean an orbital Lunar vehicle might make a better template for a Mars lander than a Lunar lander ironically; as in the crew compartment could be quickly adopted from one to the other; the Orion would be a bit cramped but a DSH could work.

Rovers built for Martian gravity should work on the Moon. They will have to be designed to lose heat by radiation. I suspect that the radiators will work on Mars.

For gravity loads, sure, but otherwise, no, it probably wouldn't work. The heat loads / temperature extremes are much too different, there's much less of a day/night swing on Mars, the Martian atmosphere is useful both as insulation for the night time and can help with taking away heat during the day, whereas in a vacuum, as on the Moon, only radiating away the heat is possible. You want to reject as much of it during the lunar day and keep as much of it during the lunar night. A rover built for Mars would overheat during the day and freeze at night on the Moon. A rover built for the Moon might work on Mars, though. Mars is much milder and is less harsh of an environment than the Moon.

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"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk"There are lies, damned lies, and launch schedules." - Larry J

I would have liked to go with Obama's original plan, get out of the space trucking business and spend money on tech development, depots, three commercial crew vehicles, a robotic lunar lander including ISRU packages and so on.

Of the provided options, and assuming SLS and Orion are not optional, I voted "Stay with the current Mars plan" which I expect will also be equivalent to "Join in an international Moon quest". Either way we are not getting funding for a HSF moon base let alone a mars lander in the forseeable future.

..so.. what we are headed for is some sort of base in high lunar orbit which will be both good preparation for a Phobos mission and interacting with asteroid material via ARM and DSH experience, and also a focus for an international moon exploration goal as described by ESA, starting with teleoperating robotic lunar missions.

Rather de-orbit ISS, we should move ISS to higher orbit, and this higher orbit could on the path to the Moon or Mars [or anywhere]. So ISS could be some sort of base in high earth orbit.So instead of station keeping for 10 years in LEO and using say 50 tons of rocket fuel to do this, you use hundreds of tons of rocket fuel to put ISS in orbit that uses less tons of rocket fuel per year for stationkeeping. Or over 50 year period one use about the same amount of rocket fuel and idea is to have ISS in orbit for +100 years.One would need more shielding and it will cost more to get to ISS. But if agree that SpaceX can and will lower launch costs, it possible that it could be cheaper to get to ISS in higher orbit, than it currently is to get to ISS in LEO.So the moving of ISS is basically a replacement for the plan to de-orbit ISS, and the focus of moving it, is to get it out of Earth's atmosphere so it doesn't have the yearly drag from Earth atmosphere.So the first "major move" does not need to get to High Earth/High lunar orbit, but at some point ISS could be latter moved to higher Earth orbits [or even Mars].The longer term purpose of moving ISS to higher orbit is to mothball ISS in regards to NASA's budget- in a sense ISS becomes more of an international station which not dependent of US or Russia to maintain it's orbit. And allowing NASA to have more budget for Mars exploration.But not allowing NASA more budget for lunar exploration which can occur before even moving ISS, but perhaps by the time, NASA sends crew to the Moon, ISS could be moved.Lunar exploration would focus on making a depot in LEO, and sending many robotic missions to the Moon, and after several years, send crew to the Moon.And all this NASA lunar exploration is focused on one task- finding minable lunar water, and have no plans for a lunar base or plans of mining lunar water.Other countries may continue with a focus with ISS, and perhaps building lunar bases. Or when Europe is involved building lunar bases, NASA focus would be focused on Mars bases.

I would have liked to go with Obama's original plan, get out of the space trucking business and spend money on tech development, depots, three commercial crew vehicles, a robotic lunar lander including ISRU packages and so on.

Of the provided options, and assuming SLS and Orion are not optional, I voted "Stay with the current Mars plan" which I expect will also be equivalent to "Join in an international Moon quest". Either way we are not getting funding for a HSF moon base let alone a mars lander in the forseeable future.

..so.. what we are headed for is some sort of base in high lunar orbit which will be both good preparation for a Phobos mission and interacting with asteroid material via ARM and DSH experience, and also a focus for an international moon exploration goal as described by ESA, starting with teleoperating robotic lunar missions.

Rather de-orbit ISS, we should move ISS to higher orbit, and this higher orbit could on the path to the Moon or Mars [or anywhere]. So ISS could be some sort of base in high earth orbit....So the first "major move" does not need to get to High Earth/High lunar orbit, but at some point ISS could be latter moved to higher Earth orbits [or even Mars].

Not possible to move ISS to a higH orbit, or at least, not possible to move it to a high enough orbit to make it a practical waypoint on the "path to the Moon or Mars."

It's not designed to be moved, for one thing. Yes, its orbit can be boosted, but it can't move very fast. Moving it fast would break it apart. However, if you move it slow, the furthest you can go is the Van Allen belts. If it went slowly through the radiation belts, its electronics would get fried. So its highest practical orbit must remain lower than the Van Allen belts.

An additional consideration is that the ISS passes through the shadow of the Earth for about half its orbit. It uses this time in Earth's shadow to radiate away heat. If it is constantly exposed to sunlight, it would overheat.

"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk"There are lies, damned lies, and launch schedules." - Larry J

I would have liked to go with Obama's original plan, get out of the space trucking business and spend money on tech development, depots, three commercial crew vehicles, a robotic lunar lander including ISRU packages and so on.

Of the provided options, and assuming SLS and Orion are not optional, I voted "Stay with the current Mars plan" which I expect will also be equivalent to "Join in an international Moon quest". Either way we are not getting funding for a HSF moon base let alone a mars lander in the forseeable future.

..so.. what we are headed for is some sort of base in high lunar orbit which will be both good preparation for a Phobos mission and interacting with asteroid material via ARM and DSH experience, and also a focus for an international moon exploration goal as described by ESA, starting with teleoperating robotic lunar missions.

Rather de-orbit ISS, we should move ISS to higher orbit, and this higher orbit could on the path to the Moon or Mars [or anywhere]. So ISS could be some sort of base in high earth orbit....So the first "major move" does not need to get to High Earth/High lunar orbit, but at some point ISS could be latter moved to higher Earth orbits [or even Mars].

Not possible to move ISS to a higH orbit, or at least, not possible to move it to a high enough orbit to make it a practical waypoint on the "path to the Moon or Mars."

It's not designed to be moved, for one thing. Yes, its orbit can be boosted, but it can't move very fast. Moving it fast would break it apart. However, if you move it slow, the furthest you can go is the Van Allen belts. If it went slowly through the radiation belts, its electronics would get fried. So its highest practical orbit must remain lower than the Van Allen belts.

An additional consideration is that the ISS passes through the shadow of the Earth for about half its orbit. It uses this time in Earth's shadow to radiate away heat. If it is constantly exposed to sunlight, it would overheat.

Well regardless of how fast one goes, ISS would have to go thru the Van Allen belts. And in terms of electronics, it seems it would not matter much how long it took to go thru the Van Allen belts AND a solar flare below the Van belts could have larger impact on electronic than passing thru the Van Allen Belts. So what you seem to be suggesting is that ISS electronics were not designed properly to withstand a significant solar flare.

As you say ISS is designed to be re boosted in order to remain in orbit, and so if one use same acceleration as designed withstand being re-boosted, it's simply a matter of having a longer duration of the boost.As far as practical waypoint to Mars. I would define such waypoint as not being a 51 inclination. And one can't change it's inclination at 400 km from Earth, whereas it's possible/practical to change it's inclination at say 20,000 km or more from Earth.I would suggest one first worry about putting into a higher orbit that doesn't require yearly reboosting due to drag from Earth atmosphere. So a minimum perigee of +800 km, but tend to think it's perigee should be above to Van Van Belt [+20,000 km]. If flying thru the Van Alan Belts, then it would have crew area shielded enough so crew are not exposed to harmful radiation from the Van Alan Belts. But outside the Van Allen Belt one would need a small portion of crew area for solar flare shelter- more shielding than ISS has now for solar flares. So something on the order of making the entire living areas able to withstand large solar flare [in it's present location] and having smaller area which is even better shielded than rest of ISS, is what you need to do to make ISS usable in higher orbit.So want to get ISS in higher orbit and usable by crew, and this doesn't necessary require that one change it's inclination. But after one does this, then international countries [or NASA] might decide at some later date to change it's inclination and make a practical waypoint to Mars.But one purpose of putting in higher orbit, is NASA could mothball it's use of ISS [though allowing other parties to use the station [and being "able to use station" means it would have at least a portion of station in which crew would not be exposed to harmful radiation during time spent at station].So NASA mothballs ISS, and other parties or NASA can un-mothballs for their use. Or nation have access to ISS- if they choose to use it. And perhaps one use, could be invest resources to make it function as a practical waypoint to Mars [or the Moon].

Rather de-orbit ISS, we should move ISS to higher orbit, and this higher orbit could on the path to the Moon or Mars [or anywhere]. So ISS could be some sort of base in high earth orbit.

There have been threads discussing this and apparently it is not feasible. I don't understand the details but I accept the authority of the opinions.

In any case I think it is at least as important to reuse the infrastructure and engineers on the ground than the hardware in orbit. We don't want to get into the situation of the Shuttle where reusing a handful of vehicles meant discarding the ability to build more. We should constantly be building more ISS-like modules and evolving new and better approaches.

I also want to see a better way of constructing bases than the ISS. I like the idea of a sort of plug and play construction that can be done robotically around phobos before sending people. I would like to see us practice these techniques in high lunar orbit.

By the time we could get around to using it, ISS will be more useful as a source of raw materials rather than as an operational station. The seals will be gone, the electronics obsolete if not fried, and other things long past their use-by date. But orbital smelting plants are so far in the future it probably is not worth saving it.

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"If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea" - Antoine de Saint-Exupéry

Rather de-orbit ISS, we should move ISS to higher orbit, and this higher orbit could on the path to the Moon or Mars [or anywhere]. So ISS could be some sort of base in high earth orbit.

There have been threads discussing this and apparently it is not feasible. I don't understand the details but I accept the authority of the opinions.

I will listen to the the authority of the opinions, despite the history of them being proven repetitively and constantly to be wrong.For example the authority of opinion was that private launch companies could not resupply ISS.And there is not enough space to give detailed list of such things- humans can't fly, only 3 computer are needed in the world, etc, etc, etc. And the Moon doesn't have water.

But just to be clear, I was against ISS, just as was against SLS. But I was fan of launching ISS at point in time when their was question about whether it should be further delayed from deciding to launch it.Now, I don't need to be proven right that we should have never built ISS, and de-obriting ISS will be pretty good proof, that we shouldn't have wasted so much money and time on ISS.

I was in favor of idea of trying to save the Shuttle by privatizing despite NASA claiming it did privatize the shuttle and that was... well, a joke. And I was favor of the Shuttle- C and thought it might possible if NASA were to actually privatize the shuttle.

I want ISS to last to end of time, not for sentimental reasons- not my sentimental reasons. Other people could be sentimental about it.But I think if we can't build orbital stations that last more than 40 years, this is going to be a problem.If we can't build houses that can't last more than 40 years, we would have a problem.Now, the Apollo sites could last longer than the pyramids- though Apollo site were not made to last very long, rather it's the nature of the Moon. Or any fool could build lunar bases which last forever, but designing a micro-gravity base, has more moving parts, and not a given that long duration orbital stations could be built to last 50 to 100 years.So I see ISS as non-deliberate protype for the design of long duration orbital stations- and that's about it regarding my sentimental attachment to ISS.And that is not very important which I will concede.I do think a main value of ISS was that it was an international project- despite that it wasn't really international, else we would not bother with wondering whether the Chinese should become involved with it.And considering Russian international behavior, with Russia it is without question involved with ISS.

The main reason to put ISS in higher orbit is to end NASA 3 billion dollar a year commitment [self-inflicted] to ISS. If I was a fan of Mars, I might become so impatient with ISS, and I could be happy to see it de-orbited, despite the possibility that blowing up 150 billion dollar project might sour support for spending trillions of dollar on some silly governmental adventure on Mars.

Now it seems to me that were one to actually believe that they was some value in an international project in space, that there would be the flip side of some negative value in destroying an international project in space. One could also imagine, one might be able to do some parlor trick to mitigate any blow back, but I think one could be deluding oneself, and that unforeseeable consequences could happen which would not be mitigated by empty gestures.

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In any case I think it is at least as important to reuse the infrastructure and engineers on the ground than the hardware in orbit. We don't want to get into the situation of the Shuttle where reusing a handful of vehicles meant discarding the ability to build more. We should constantly be building more ISS-like modules and evolving new and better approaches.

It doesn't seem to me that by not destroying ISS, one is preventing other orbital stations from being built.In fact I see this as superstitious [not a fan of]. Rather I see keeping ISS is more a factor of causing more orbital stations being made. Not that I am fan of this. I don't want to de-orbit ISS because I don't want space exploration to stop, before it has begun. And don't think making orbital space stations has much to do with space exploration.

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I also want to see a better way of constructing bases than the ISS. I like the idea of a sort of plug and play construction that can be done robotically around phobos before sending people. I would like to see us practice these techniques in high lunar orbit.

I don't. But but it seems fairly clear that de-orbiting ISS would be path in the opposite direction of what you want.

By the time we could get around to using it, ISS will be more useful as a source of raw materials rather than as an operational station. The seals will be gone, the electronics obsolete if not fried, and other things long past their use-by date. But orbital smelting plants are so far in the future it probably is not worth saving it.

I think using +100 tons of GEO non-operational Sats as better scrap.Though I might favor scrapping ISS at some point, there would probably be much more people who didn't want to use ISS as scrap. I can imagine a distant future of protesters at congress doors arguing against such practical uses of an old station.

I don't see HSF as a short term goal.science is a goal. exploration is a goal. so is technology and economy.Humans in space, like girrafs under water, should be there only when they must.

Cost effectiveness should be the measure of scale, not adventure.

edit: voted for joining international moon for if that happens, Nasa should not be left outside.

You have strong opinions, but it is good you understand how being left out may have ramifications.

For the near future, all we know is NASA will have a Moon orbiter, a big rocket, and a lot of potential partners all eyeing the Moon. If we won't be landing on Mars for another 15 years, may as well spend 10 of them landing on the Moon considering 'THE PLAN' NASA's allegedly is going by dictates time in 'The Proving Ground.' Frankly it just depends on how much any partners can contribute, and they've already prioritized Luna over Mars.

The USA does not need another refocus of what to do in space. Every time there is a refocus the POR get's brushed aside and a new one is put in place.

Of all the many dozens of HSF plans put into motion in the past 40 decades less than a handfull actually became reality: STS and the space station. All other lofty goals, including many Moon plans and many Mars plans came to nothing.

Rather de-orbit ISS, we should move ISS to higher orbit, and this higher orbit could on the path to the Moon or Mars [or anywhere]. So ISS could be some sort of base in high earth orbit.

There have been threads discussing this and apparently it is not feasible. I don't understand the details but I accept the authority of the opinions.

The biggest issue limiting the lifetime of ISS is the structure. Docking, berthing, and thermal cycles introduce micro fractures. Eventually, the structure becomes unsafe. That's why 2024 or 2028 are considered to be end of life for ISS.

Newer ISS modules could be used to as the basis for a new space station. The Russians were thinking about saving their newer modules. However, I don't think anyone has the money for that.

I think NASA or even SpaceX should at least send some ISRU equipment to the moon to test how hard it would be to manufacture lox, or obtain other materials. This equipment could also be used on Mars. The only other reason is to explore the polar regions and craters for water. Otherwise, no real reason.

If Lox could be made and thrown into orbit via electromagnetic rail. Capture and take to a fuel depot at one of the LaGrange points, then it would be worth the effort. With a refueling depot in LEO and one at an L point, a robust Mars transportation infrastructure could be build. It would be great if all spacefaring nations could work together on this.

Rather de-orbit ISS, we should move ISS to higher orbit, and this higher orbit could on the path to the Moon or Mars [or anywhere]. So ISS could be some sort of base in high earth orbit.

There have been threads discussing this and apparently it is not feasible. I don't understand the details but I accept the authority of the opinions.

The biggest issue limiting the lifetime of ISS is the structure. Docking, berthing, and thermal cycles introduce micro fractures. Eventually, the structure becomes unsafe. That's why 2024 or 2028 are considered to be end of life for ISS.

I doubt it.Though if you included micrometeorite impact damage, that could be more convincing.If ISS is crashed into our atmosphere in 2028, then ISS would be about as old as the Shuttle.It seems unlikely that ISS has had an equal or greater amount of structural damage per year as the Shuttle orbiters.

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Newer ISS modules could be used to as the basis for a new space station. The Russians were thinking about saving their newer modules. However, I don't think anyone has the money for that.

The Soviets always cause trouble.A saner person flees from it, and there is lots doing so- one might hope they continue have somewhere to flee to. And one could imagine it doesn't look good.The economic contrast between NASA and Russian Space agency is interesting. In overly simplistic terms,imagine what the Russian Space agency could do if it had NASA's budget?Of course it does not remotely work that way, obviously Russian corruption makes American government corruption seem insignificant/civilized, though in terms of quantity money, the Russians are taking rubles vs dollars.